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Method for producing trichlorosilane

a technology of trichlorosilane and trichlorosilane, which is applied in the direction of organic compounds/hydrides/coordination complex catalysts, physical/chemical process catalysts, silicon compounds, etc., can solve the problems of difficult to produce trichlorosilane, difficult to remove methyldichlorosilane, and the content of carbon impurities becomes a problem, so as to reduce the amount of chlorosilane discarded together with

Inactive Publication Date: 2017-12-28
SHIN ETSU CHEM IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a simplified method for achieving high-purification of trichlorosilane at an improved yield. This is achieved by converting methyldichlorosilane into methyltrichlorosilane through redistribution of chlorine atoms between the two compounds, making impurities easier to remove. This reduces the need for distillation and reduces the amount of chlorosilane discarded.

Problems solved by technology

Accordingly, the content of carbon impurities also becomes a problem in a semiconductor grade polycrystalline silicon.
It is, however, not easy to produce trichlorosilane with a carbon-containing compound being sufficiently removed.
In particular, methyldichlorosilane is difficult to be removed, because it is as a major component of the methylchlorosilanes and also it has a boiling point (41° C.) close to the boiling point (32° C.) of trichlorosilane to be purified by distillation.

Method used

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  • Method for producing trichlorosilane
  • Method for producing trichlorosilane
  • Method for producing trichlorosilane

Examples

Experimental program
Comparison scheme
Effect test

example 1

Effect of Redistribution of Chlorine

[0067]A packed tower filled with a weakly basic anion-exchange resin having dimethylamine as a functional group AMBERLYST B20-HGDRY (registered trademark) (Organo Corporation) was vacuum dried to a water content of 2 wt % or less. The effect of redistribution of methylchlorosilane was then inspected. A Teflon (registered trademark) tube with a diameter of 9.7 mm and a length of 900 mm was used for the packed tower.

[0068]The liquids of trichlorosilane with a content of methyldichlorosilane of 1,500 ppmwt and an equimolar amount of tetrachlorosilane were passed through the packed tower. The packed tower was maintained at 60 to 80° C., and the supply was performed at a superficial flow velocity of 2.25 m / hr.

[0069]The quantities of methyldichlorosilane (CH3HSiCl2) and methyltrichlorosilane (CH3SiCl3) in methylsilanes contained in the product mixture obtained from the packed tower were determined. More specifically, the analysis was performed by gas ch...

example 2

Reduction in Degree of Conversion With Catalyst Poisoned With Boron Trichloride

[0071]Tetrachlorosilane (SiCl4) to which 0.1 wt % boron trichloride solution had been added as Lewis acid was passed through the same catalyst as that used in Example 1, and then the redistribution reaction treatment of dichlorosilane (SiH2Cl2) and tetrachlorosilane (SiCl4) was performed to examine the activity of catalysts. The results are shown in Table 2.

TABLE 2ReactiontemperatureSiH2Cl2SiHCl3SiCl4BCl3° C.Wt %Wt %Wt %Raw material——16.5083.5AMBERLYSTBefore450.543.456.4B20•HGDRY ™passingliquidAfter456.925.567.1passingliquid

[0072]After passing the boron trichloride solution, the yield of trichlorosilane (HSiCl3) decreased, so that the reduction in catalyst activity is perceived. Accordingly, in the redistribution reaction of methyldichlorosilane (CH3HSiCl2) also, it can be expected that the removal of Lewis acid (aluminum chloride) in tetrachlorosilane (SiCl4) to be supplied and the removal of Lewis acid ...

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Abstract

In order to produce high-purity trichlorosilane by removing methyldichlorosilane from a mixture (S) containing methyldichlorosilane (CH3HSiCl2), tetrachlorosilane (SiCl4), and trichlorosilane (HSiCl3) in the method for producing trichlorosilane of the present invention, a procedure is employed in which chlorine atoms are redistributed between methyldichlorosilane and tetrachlorosilane through catalytic treatment for conversion into trichlorosilane and methyltrichlorosilane (CH3SiCl3). Methyldichlorosilane (boiling point: 41° C.) having a boiling point close to that of trichlorosilane (boiling point: 32° C.) to be purified is converted into methyltrichlorosilane (boiling point: 66° C.) having a higher boiling point through redistribution of chlorine atoms between methyldichlorosilane and tetrachlorosilane, achieving easy removal of impurities.

Description

TECHNICAL FIELD[0001]The present invention relates to a method for producing trichlorosilane, and more particularly, to technique for easily separating trichlorosilane and methyldichlorosilane so as to obtain high-purity trichlorosilane.BACKGROUND ART[0002]Trichlorosilane (HSiCl3) has been used as a raw material of high-purity polycrystalline silicon for use in production of a silicon wafer and the like since long ago. Many synthetic methods are known for obtaining trichlorosilane. For example, in Japanese Patent Laid-Open No. 56-73617 (Patent Literature 1), an invention relating to a method for producing trichlorosilane is disclosed, in which silicon tetrachloride as a byproduct of the production of trichlorosilane is efficiently converted into trichlorosilane.[0003]In addition to this, the following methods for producing trichlorosilane are also known.[0004]In Japanese Patent Laid-Open No. 2-208217 (Patent Literature 2), Japanese Patent Laid-Open No. 9-169514 (Patent Literature 3)...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C01B33/107B01J31/08B01J31/02
CPCC01B33/10778C01B33/10773C01B33/1071B01J31/08B01J31/0237
Inventor ISHIDA, MASAHIKOSAITO, HIROSHIHASEGAWA, MASAYUKI
Owner SHIN ETSU CHEM IND CO LTD